One of the main functions of the musculature of S. mansoni is to allow the parasite to maintain its position in the host. Most antischistosomal drugs eventually interfere with schistosome motor activity by direct or indirect interaction with its musculature. At present little is known about the mechanical and biophysical properties of the muscles or the way in which the nervous system controls the musculature. The main objective of the proposed study is to determine these properties and how drugs interact with the nervous system and musculature. This will be accomplished using electrophysiological techniques to: a) analyze the basic properties of the tegument, the muscle and nervous system and b) analyze the manner in which antischistosomal compounds interfere with the normal functioning of these systems. Intracellular and extracellular recording techniques will be employed. Results of these neurobiological studies may point to possibilities for rational development of agents which could be effective therapeutic agents against schistosomes because they specifically disrupt nerve or muscle functioning in schistosomes.